// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Functions to canonicalize "standard" URLs, which are ones that have an
// authority section including a host name.

#include "url/url_canon.h"
#include "url/url_canon_internal.h"
#include "url/url_constants.h"

namespace url {

namespace {

    template <typename CHAR, typename UCHAR>
    bool DoCanonicalizeStandardURL(const URLComponentSource<CHAR>& source,
        const Parsed& parsed,
        CharsetConverter* query_converter,
        CanonOutput* output,
        Parsed* new_parsed)
    {
        // Scheme: this will append the colon.
        bool success = CanonicalizeScheme(source.scheme, parsed.scheme,
            output, &new_parsed->scheme);

        // Authority (username, password, host, port)
        bool have_authority;
        if (parsed.username.is_valid() || parsed.password.is_valid() || parsed.host.is_nonempty() || parsed.port.is_valid()) {
            have_authority = true;

            // Only write the authority separators when we have a scheme.
            if (parsed.scheme.is_valid()) {
                output->push_back('/');
                output->push_back('/');
            }

            // User info: the canonicalizer will handle the : and @.
            success &= CanonicalizeUserInfo(source.username, parsed.username,
                source.password, parsed.password,
                output,
                &new_parsed->username,
                &new_parsed->password);

            success &= CanonicalizeHost(source.host, parsed.host,
                output, &new_parsed->host);

            // Host must not be empty for standard URLs.
            if (!parsed.host.is_nonempty())
                success = false;

            // Port: the port canonicalizer will handle the colon.
            int default_port = DefaultPortForScheme(
                &output->data()[new_parsed->scheme.begin], new_parsed->scheme.len);
            success &= CanonicalizePort(source.port, parsed.port, default_port,
                output, &new_parsed->port);
        } else {
            // No authority, clear the components.
            have_authority = false;
            new_parsed->host.reset();
            new_parsed->username.reset();
            new_parsed->password.reset();
            new_parsed->port.reset();
            success = false; // Standard URLs must have an authority.
        }

        // Path
        if (parsed.path.is_valid()) {
            success &= CanonicalizePath(source.path, parsed.path,
                output, &new_parsed->path);
        } else if (have_authority || parsed.query.is_valid() || parsed.ref.is_valid()) {
            // When we have an empty path, make up a path when we have an authority
            // or something following the path. The only time we allow an empty
            // output path is when there is nothing else.
            new_parsed->path = Component(output->length(), 1);
            output->push_back('/');
        } else {
            // No path at all
            new_parsed->path.reset();
        }

        // Query
        CanonicalizeQuery(source.query, parsed.query, query_converter,
            output, &new_parsed->query);

        // Ref: ignore failure for this, since the page can probably still be loaded.
        CanonicalizeRef(source.ref, parsed.ref, output, &new_parsed->ref);

        return success;
    }

} // namespace

// Returns the default port for the given canonical scheme, or PORT_UNSPECIFIED
// if the scheme is unknown.
int DefaultPortForScheme(const char* scheme, int scheme_len)
{
    int default_port = PORT_UNSPECIFIED;
    switch (scheme_len) {
    case 4:
        if (!strncmp(scheme, kHttpScheme, scheme_len))
            default_port = 80;
        break;
    case 5:
        if (!strncmp(scheme, kHttpsScheme, scheme_len))
            default_port = 443;
        break;
    case 3:
        if (!strncmp(scheme, kFtpScheme, scheme_len))
            default_port = 21;
        else if (!strncmp(scheme, kWssScheme, scheme_len))
            default_port = 443;
        break;
    case 6:
        if (!strncmp(scheme, kGopherScheme, scheme_len))
            default_port = 70;
        break;
    case 2:
        if (!strncmp(scheme, kWsScheme, scheme_len))
            default_port = 80;
        break;
    case 7:
        if (!strncmp(scheme, kHttpSuboriginScheme, scheme_len))
            default_port = 80;
        break;
    case 8:
        if (!strncmp(scheme, kHttpsSuboriginScheme, scheme_len))
            default_port = 443;
        break;
    }
    return default_port;
}

bool CanonicalizeStandardURL(const char* spec,
    int spec_len,
    const Parsed& parsed,
    CharsetConverter* query_converter,
    CanonOutput* output,
    Parsed* new_parsed)
{
    return DoCanonicalizeStandardURL<char, unsigned char>(
        URLComponentSource<char>(spec), parsed, query_converter,
        output, new_parsed);
}

bool CanonicalizeStandardURL(const base::char16* spec,
    int spec_len,
    const Parsed& parsed,
    CharsetConverter* query_converter,
    CanonOutput* output,
    Parsed* new_parsed)
{
    return DoCanonicalizeStandardURL<base::char16, base::char16>(
        URLComponentSource<base::char16>(spec), parsed, query_converter,
        output, new_parsed);
}

// It might be nice in the future to optimize this so unchanged components don't
// need to be recanonicalized. This is especially true since the common case for
// ReplaceComponents is removing things we don't want, like reference fragments
// and usernames. These cases can become more efficient if we can assume the
// rest of the URL is OK with these removed (or only the modified parts
// recanonicalized). This would be much more complex to implement, however.
//
// You would also need to update DoReplaceComponents in url_util.cc which
// relies on this re-checking everything (see the comment there for why).
bool ReplaceStandardURL(const char* base,
    const Parsed& base_parsed,
    const Replacements<char>& replacements,
    CharsetConverter* query_converter,
    CanonOutput* output,
    Parsed* new_parsed)
{
    URLComponentSource<char> source(base);
    Parsed parsed(base_parsed);
    SetupOverrideComponents(base, replacements, &source, &parsed);
    return DoCanonicalizeStandardURL<char, unsigned char>(
        source, parsed, query_converter, output, new_parsed);
}

// For 16-bit replacements, we turn all the replacements into UTF-8 so the
// regular code path can be used.
bool ReplaceStandardURL(const char* base,
    const Parsed& base_parsed,
    const Replacements<base::char16>& replacements,
    CharsetConverter* query_converter,
    CanonOutput* output,
    Parsed* new_parsed)
{
    RawCanonOutput<1024> utf8;
    URLComponentSource<char> source(base);
    Parsed parsed(base_parsed);
    SetupUTF16OverrideComponents(base, replacements, &utf8, &source, &parsed);
    return DoCanonicalizeStandardURL<char, unsigned char>(
        source, parsed, query_converter, output, new_parsed);
}

} // namespace url
